Division of my grand mothers property

Hi Sirs, My grand mother's father had given a 1650 sq ft to my grand mother. In the will, he had mentioned that until my grand mother is alive, the property cannot be divided or mortgaged or sold off. My grand mother passed away 1.5 years back. My father is not keeping good health. My mother passed away in 2012. currently 1000 sq ft of area has been build into 3 floor house. and rest 650 sq ft is unbuilt. I have 1 brother and 1 sister. My brother is currently living with my father. Even though I dont live with my father, I have very good relation with him. I have provided close to 15 Lakh finance support to my father in last 8 years. This financial support includes hospital expenses of my father and 10 lac business finance support to my brother. In this scenario, is there any chance that I might not receive any share of property from my father. I am asking this because, my father is trying to planning give me 650 of unbuilt property to me and the rest 1000 sq ft of built up property to my sister and brother. My sister might not be interested in the property as she has enough money and most probably the whole 1000 sq ft of built up property might go to my brother. This is some thing that is concerning me as I think it is not fair to me. Can you suggest, in case this happens, can i take this to court. Or is there something that I can do to get fair amount of share.